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R380 gearbox lubrication
Nigel Steward (Red 1038) with a Factory MGBGTV8 from Hampshire posted a note on the Bulletin Board on the V8 website concerning lubrication for an R380 gearbox. (Dec 02)

I have had the later R380 gearbox (the one fitted to RV8s from VIN 0644) in my MGBGTV8 for some five years and am delighted with it. I have found the R380 gearbox seems to be rather more viscosity sensitive than performance level sensitive. However I am becoming confused as to which transmission oil to use. When the gearbox was first fitted, I was recommended to use oil to Dexron II specification - this is "Red" ATF (Automatic Transmission Fluid"). I understand that some time in the late 1990s, Land Rover changed their recommendation from Red ATF to MTF-9 which I believe is a fully synthetic Texaco product. As an aside I gather that Castrol recommend their semi-synthetic VMX80 for the R380. Can anyone guide me as to the best oil for the R380 gearbox please?

Keith Baylis at Ames MG at Bury St Edmunds responded: "I have had a look at your query over gearbox oil for the R380 box fitted to the later RV8s. Initial enquiries did not go too well so I have called Castrol and spoke with their technical department. They have said that according to their information, the R380 gearboxes from 1994 to 1998 used "Dextron II" automatic gearbox oil, but Dextron III can also be used."

Richard Dunn (Woodcote Green 1056) from Buckinghamshire posted a note "the RV8 Repair Manual lists all the products previously listed along with Shell Dexron 11D or Donax TG, Esso Auto Transmission Fluid and Duckhams Uni-Matic or D-Matic. I note from my most recent service at Brown & Gammons that they have put in two litres of Dextron II."

Roger Parker responded with the following information:
Gearbox Lubricant

LT77 up to 1994 - SD1 series gearboxes and those in the RV8 up to VIN 0644. Castrol TQF Auto Trans Fluid or other makers equivalent.

R380 in all production RV8s after VIN 0644 and any other R380 made up to 1998. Castrol Dextron II or Dextron III or other makers equivalent.

R380 made from 1998 Castrol SMX-S synthetic oil or other makers equivalent.

Roger Parker subsequently provided an update based on his further research. "The R380 production change was notified to all dealers indicating that in August 1998 the R380 gearbox and the lubrication changed to MTF94. It is clear that no gearbox bought before that date would be to the new specification but quite possible that some old stock bought after the change date might have been old specification R380 boxes. Where the RV8 was used as the base comparison reference to identify an original R380 part number, it is clear that even today the version obtained may well still be an older specification gearbox, although a part number supercession would be a clear indicator that this was not so."

"It would be of considerable help to me if members with cars featuring an R380 gearbox could provide me with the actual gearbox number. This is stamped into an oval boss casting lump on the right side of the main gearbox case (the cast iron part) right at the bottom of the gearbox. Most valuable is the prefix to the individual number because with all previous specification change cases with LT77, a new sequence has started.

This information and continued enquiry should then provide a definite way of identifying a gearbox even when it is grubby and sitting on the garage floor with no details of the vehicle from which it has come."
"Incidentally, MTF94 is a Texaco product and the standard lubrication for the PG1 series of gearboxes that are found in many current Rover vehicles including all manual MGF, ZS, ZT and all ZR cars except the 1.4. Interestingly I have a document which indicates that the performance of Castrol SMX-S is actually better than MTF94 - something that will be of definite advantage if the gearbox has to handle high torque levels."

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